[IndexedDB] Pool and evict leveldb iterators, to save memory

content/browser/indexed_db/mock_browsertest_indexed_db_class_factory.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_INDEXED_DB_MOCK_BROWSERTEST_INDEXED_DB_CLASS_FACTORY_H_
 #define CONTENT_BROWSER_INDEXED_DB_MOCK_BROWSERTEST_INDEXED_DB_CLASS_FACTORY_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 37 matching lines @@
       const IndexedDBDatabase::Identifier& unique_identifier) override;
   std::unique_ptr<IndexedDBTransaction> CreateIndexedDBTransaction(
       int64_t id,
       IndexedDBConnection* connection,
       const std::set<int64_t>& scope,
       blink::WebIDBTransactionMode mode,
       IndexedDBBackingStore::Transaction* backing_store_transaction) override;
   scoped_refptr<LevelDBTransaction> CreateLevelDBTransaction(
       LevelDBDatabase* db) override;
   std::unique_ptr<LevelDBIteratorImpl> CreateIteratorImpl(
-      std::unique_ptr<leveldb::Iterator> iterator) override;
+      std::unique_ptr<leveldb::Iterator> iterator,
+      LevelDBDatabase* db,
+      const leveldb::Snapshot* snapshot) override;
 
   void FailOperation(FailClass failure_class,
                      FailMethod failure_method,
                      int fail_on_instance_num,
                      int fail_on_call_num);
   void Reset();
 
  private:
   FailClass failure_class_;
   FailMethod failure_method_;
   std::map<FailClass, int> instance_count_;
   std::map<FailClass, int> fail_on_instance_num_;
   std::map<FailClass, int> fail_on_call_num_;
   bool only_trace_calls_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_INDEXED_DB_MOCK_BROWSERTEST_INDEXED_DB_CLASS_FACTORY_H_